Method and apparatus for controlling the level of a molten material in a glass manufacturing system

Abstract

A method of feeding a pulverulent batch material into a furnace in the manufacture of glass. The pulverulent batch material is fed from a first bulk batch feeder at a first batch feed rate, and from a second trim batch feeder at a second trim batch feed rate. The trim batch feed rate is equal to or less than 10% of the total batch feed rate. The use of trim electrodes and trim burners is also disclosed.

1. A method of forming a glass melt comprising:
 providing a glass-forming batch material; 
 feeding the batch material into a furnace from a bulk batch feeder at a bulk batch feed rate; 
 feeding the batch material into the furnace from a trim batch feeder at a trim batch feed rate equal to or less than 10% of a total batch feed rate that is the sum of the bulk batch feed rate and the trim batch feed rate; 
 heating the batch material in the furnace to form a glass melt; 
 determining a level of the glass melt; and 
 varying the trim batch feed rate in response to the level of the glass melt while maintaining the bulk batch feed rate constant. 
 
     
     
       2. The method according to  claim 1  wherein the trim batch feed rate is equal to or less than 5% of the total feed rate. 
     
     
       3. The method according to  claim 1  wherein the trim batch feed rate is equal to or less than 3% of the total feed rate. 
     
     
       4. The method according to  claim 1  wherein the feeding at a bulk batch feed rate comprises feeding the batch material from a plurality of bulk batch feeders. 
     
     
       5. The method according to  claim 1  wherein the determining the level of the glass melt comprises sensing the level of the melt with a sensor. 
     
     
       6. The method according to  claim 5  wherein the level of the glass melt is sensed downstream of the furnace. 
     
     
       7. The method according to  claim 5  wherein the sensed level of the glass melt is compared to a predetermined level value, and the difference between the sensed level and the predetermined level value is used to vary the trim batch feed rate. 
     
     
       8. The method according to  claim 1  wherein the heating is performed by heating means, and a power output of the heating means is varied proportional to the variation in trim batch feed rate. 
     
     
       9. The method according to  claim 8  wherein the heating means is a combustion flame. 
     
     
       10. The method according to  claim 8  wherein the heating means is an electric current. 
     
     
       11. A method of maintaining a substantially constant level of a glass melt in a furnace comprising:
 providing a glass-forming batch material; 
 feeding the batch material into the furnace from a first batch feeder at a first batch feed rate; 
 feeding the batch material into the furnace from a second batch feeder at a second batch feed rate equal to or less than 3% of a total batch feed rate; 
 heating the batch material in the furnace to form the glass melt; 
 determining a level of the glass melt; and 
 varying the second batch feed rate in response to the level of the glass melt. 
 
     
     
       12. The method of according to  claim 11  wherein the determining comprises a level sensor located downstream of the melting furnace. 
     
     
       13. The method according to  claim 11  wherein the heating is performed by heating means, and a power output of the heating means is varied proportional to the variation in the second batch feed rate. 
     
     
       14. The method according to  claim 11  wherein the determined level of the glass melt is compared to a predetermined level value, and the difference between the determined level and the predetermined level value is used to vary the trim batch feed rate. 
     
     
       15. The method according to  claim 11  wherein the first batch feed rate is maintained substantially constant during the varying of the second batch feed rate.